[vdr] Re: Mux A / Channel 5 UK DVB-T broken with VDR, dvbstreamworks...

[Marko Myllymaa <myllymaa@niksula.hut.fi>]

On Thu, 9 Jan 2003, Gregor Lawatscheck wrote:

> There appears to be a bug handling MPEG streams from the UK DVB-T Multiplex
> A (mux A) with vdr. I've tested versions 1.0.4, 1.1.13, 1.1.16 and 1.1.20
> with the old and NEWSTRUCT drivers. All other Multiplexes are fine (both
> QAM16 and QAM 64 ones).
>
> Mux A in the UK most importantly carries Channel 5 (C5) and (up until Jan
> 13) Sky News and no matter how good a tuning I manage to adjust, I get
> constant cut-outs in the stream. It's not the usual blockiness or freeze in
> the picture when the reception is bad but it looks more like some of the
> pictures are repeated in succession (syncing problem? buffer?). The
> cut-outs are especially noticable in fast movements like sports coverage.
> Unfortunately vdr doesn't output any special errors related to this to the
> message log.
>
> Using dvbstream to output to a fifo-file and playing back this fifo-file in
> realtime with mplayer to -ao mpegpes -vo mpegpes works fine (!!) and
> without any cut-outs or repeated images in the stream. Recording files from
> C5 in vdr and then playing them back in mplayer to -ao / -vo mpegpes shows
> the same errors as watching the channel live in vdr. Strange isn't it... I
> seriously didn't think this could be caused by vdr and faffed about with
> the tuning on and off through the past few months...
>
> The fact it reproducibly works fine with dvbstream -> fifo -> mplayer ->
> DVB-S card but fails in vdr makes me think the error must lie with vdr
> rather than with the driver or the tuning or anything else! I have
> double-checked QAM, FEC, transmission mode, guard interval and bandwidth
> settings to correspond between dvbstream and the vdr config for the mux in
> question. What I'm wondering is why ( at least in the past year) no one
> else seems to have noticed any problems regarding Channel 5 and DVB-T using
> vdr? Are you all blaming your tuning or is it just that no one else can
> reproduce this problem? I'm using the Oxford transmitter if that is of any
> value. I've googled and searched the vdr-mailinglist without finding
> reports about any similar stories.
>
> What would be the best way to debug this? I'm willing to help and go
> through source-code if other people can reproduce this and give me some
> pointers. Let's get this fixed...

I think I'm having the same problem here in Finland. With nova-t card and
dxr3 in the system also.
At least subtv looks very bad, the image pauses for couple frames once in
a second (or two). But that isn't always like it. I recorded Stargate this
week and it looks sometimes just fine. And the suddenly it starts this
stuttering.. and it stutters for awhile and then its fine again. This
repeats many times during one show.

And its the same with live TV or with recordings. And I have this problem
with other channels also, with Yle's channels and mtv3.. I haven't watched
nelonen that much that I cannot remember how it behaves.

I haven't tried playback with dvbstream yet.

First I thought that my machine is too slow (it's pentium 200MMX), but
'top' says that there is about 30% cpu idle all the time.
Then I thought that my receiving is poor as I have only small table top
antenna. But in windows (other computer also) it works just fine. And I
live about 10 kilometers from the broadcasting antenna mast. So it cannot
be that.

I'll but a little recording to my web site tomorrow. So you can check how
it looks.

Don't know if this helps, but:
Actually, now that my brains remembered it, it looks kinda same as one dvd
I tried to watch, Netforce. Only difference is that the dvd does this
stuttering all the time..
And it does that with toxine.
Mplayer works fine, but it has cräppy subtitles with dxr3.

I could also add my little free time on this to hunt down some bugs.


  Marko Myllymaa

--
Marko Myllymaa     | home: 09-547 1907, 044-371 6464 work: 09-451 5855
Kilonrinne 10 A 14 | myllymaa@iki.fi
02610 Espoo        | marko.myllymaa@tml.hut.fi




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